1. Field of the Invention
The present invention relates generally to a transfer system, which is provided in a vacuum process equipment for an object to be processed, such as a semiconductor wafer or an LCD substrate, for carrying the object into/out of a process chamber.
2. Description of the Related Art
In each of processes for producing semiconductor devices, a transfer system is used for delivering a semiconductor wafer serving as an object to be processed, from a clean room to a process chamber for carrying out a predetermined process, or for delivering a processed semiconductor wafer from the process chamber to the clean room.
As transfer arms serving as transfer systems, there are known a selective compliance assembly robot arm (SCARA) type single pickup, an SCARA type twin pickup, an SCARA dual arm type, a frog leg type and so forth. All of these transfer arms have an articulated structure wherein an arm is pivotably connected. The arm has a swivel mechanism on the proximal end side thereof, and a pick for supporting a semiconductor wafer on the tip side thereof, so as to transfer the wafer by the swiveling motion of the arm and the telescopic motion of a joint portion.
However, the above described transfer systems, such as the SCARA type twin pickup, the SCARA dual arm type and the frog leg type, have a structure complicated by the articulated structure. Therefore, the above described transfer systems have a high rate of occurrence of dust, lack in reliability on transfer and increase costs. In addition, if the transfer system is provided in a load-lock chamber of a semiconductor process equipment, it is required to ensure a space for the swiveling and telescopic motions of the arm, so that the size of the load-lock chamber is increased to cause the increase of the size and costs of the whole system.